The present invention is a method for the preparation of carbinol-functional organosiloxanes and carbinol functional organosiloxane resins. The method comprises contacting a cyclic silyl ether with an organosiloxane or an organosiloxane resin at a temperature within a range of about 25.degree. C. to 150.degree. C. The method may be conducted in the presence of an inert organic solvent to facilitate dissolution and contact of the reactants.
Several methods for preparation of cyclic silyl ethers useful in the present invention have been described. For example, Knoth et al., J. Am. Chem. Soc. 80:4106, 1958, describe the preparation of various 2,2-disubstituted 1-oxa-2-silacycloalkanes by heating the corresponding (chloroalkyoxy)chlorosilanes with metallic sodium or lithium. Knoth et al. further report that the cyclic silyl ethers can be hydrolyzed to form the corresponding bis(hydroxyalkyl)tetraalkyldisiloxanes. Speir et al.. J. Org. Chem. 25:1637, 1960, teach that 1,3-bis(hydroxypropyl) tetramethyldisiloxane prepared by the methanolysis of 1,3-bis(acetoxypropyl)tetramethyldisiloxane loses water during distillation to form 2,2-dimethyl-1-oxa-2-silacyclopentane. Speir et al. further teach that the equilibrium can be shifted in favor of the cyclic silyl ether by use of a drying agent such as lime during the distillation process. Knoth. U.S. Pat. No. 2,983,744, issued May 9, 1961, describes a process for the production of cyclic silyl ethers, the process involving reacting with two equivalents of an alkali metal or alkaline earth metal an omega-halogenoalkoxydihydrocarbohalogenosilane. Knoth further reports that the 2,2-dihydrocarbo-1-oxa-2-silacycloalkanes prepared by the described method are readily converted by hydrolysis to long chain oxadisila-alpha,omega-diols. Berger, U.S. Pat. No. 3,505,380, issued Apr. 7. 1970, describes a hydrosilation process for preparing cyclic silyl ethers, the process comprising contacting in the presence of platinum catalyst a mixture of an unsaturated silicon hydride, unsaturated silicon compound, and silicon hydride. Chen et al., Organometallics 6:2590, 1987, teach the preparation of cyclic silyl ethers by adding triphenylmethyl perchlorate to a methylene chloride solution of the corresponding silyl hydride.
All of the above described methods are useful for making cyclic silyl ethers useful in the present claimed method. However, a preferred method is described by Mironov et al., Zhurnal Obshchei Khimii 39:966, 1969. Mironov et al. teach that (methallyloxy)dimethylsilane in the presence of a platinum catalyst can undergo an intramolecular hydrosilation reaction to form the corresponding 1-oxa-2-silacycloalkane.
Gol'din et al., Zhurnal Obshchei Khimii 45:2451, 1975, teach a process for the preparation of carbofunctional siloxanes. The process involves the reaction of cyclosiloxanes with carbofunctional disiloxanes containing hydroxy-, carboxy-, acyloxy-, or cyano-terminal groups in the presence of a catalytic ion-exchange resin.
The present invention is a method which can yield a near quantative yield of carbinol-functional organosiloxanes and carbinol-functional organosiloxane resins. The method does not require a catalyst and can be conducted by contacting a cyclic silyl ether with an organosiloxane or an organo siloxane resin at a temperature within a range of about 25.degree. C. to 150.degree. C.
Carbinol-functional organosiloxanes and carbinol-functional organosiloxane resins prepared by the present method may be useful, for example, to form silicone and urethane copolymers, and to modify organic resins, coatings, paints, foams, and elastomers.